I might have spoken too soon. The speed will show itself properly when under about 5KB/s, but as soon as it get higher than that, it's only displayed at 12.8KB increments(which it half of what it was with v4.1).

Using FlashFXP v4.2.2 build 1760, unregistered on WinXP SP3
No firewall(except on the router) or antivirus and using a DSL 6Mb down, 800Kb up